Grinding machine



Aug. 31, 1937. N. cHAcE. JR

GRINDING MACHINE Original Filed July 28, 1932 3 Sheets-Sheet 1 3w, NW .C m \Nw 1 mm 7w) Y J \7/ mm, /t n h w my MU H Qha/ AUNINV /M F W ,v N P m 88 1 WN N I I N% M N N QW NM w QW WW RN NM Qw m QM QN INVENTOR M/Wza/z B. mace, :77.

BY M W m? ATTORNEYS Aug. 31, 1937. N. B. cHAcE, JR 2,091,469

GRINDING MACHINE Original Filed July 28, 1932 3 Sheets-Sheet 2 J3 zy 1 I 462 4 JJ 5% 7 J0 1 I 21 w 41 I INVENTOR J o rnz Q72 B. mace, J:

BY MW ATTORNEY Aug. 31, 1937. c c JR 2,091,469

GRINDING MACHINE Original Filed July 28, 1932 3 Sheets-Sheet 3 NVENTOR v Mrnzan akacegzfzr BY M W 4 ATTORNEYS Patented Aug. 31, 1937 UNITED STATES PATENT OFFICE GRINDING MACHINE Norman E. Chace, Jr.,

Detroit, Mich., assignor to Ray Day Piston Corporation of Detroit, Detroit, Mich., a corporation of Delaware Application July 28, 1932, Serial No. 625,327

Renewed February 15, 1937 7 Claims.

machine capable of grinding pistons in an improved manner so as to provide a pair of opposed walls which have a cylindrical contour or outer surface and a second pair of opposed walls adjacent the wrist pin bosses having an outer surface or contour which is out-of-round and preferably tapered longitudinally of the piston. Another feature of the invention is to provide a method of grinding a piston so that two of the outer walls of the piston are cylindrical and the other two opposite walls are out-of-round. Another object of the invention is to provide a method whereby the entire peripheral wall of the piston may be ground, but wherein two opposite faces only of the piston wall are ground slightly out-of-round, and in which the grinding is accomplished on a taper longitudinally of the piston.

Other objects and advantages of the invention will appear from the following description and appended claims when considered in connection with the accompanying drawings forming a part of this specification. In said drawings:

Fig. l is a fragmentary front elevation of a grinding machine showing one form of my invention applied thereto.

Fig. 2 is a side elevation taken substantially along the line 2-2 of Fig. 1, looking in the direction of the arrows.

Fig. 3 is a sectional View, partly in elevation, taken substantially along the line 3-3 of Fig. 2, looking in the direction of the arrows.

Fig. 4 is a section taken substantially alon the line 4-4 of Fig. 3.

Fig. 5 is a side elevation, partly in section, taken I substantially along the line 55 of Fig. 1, looking in the direction of the arrows.

Fig. 6 is a sectional view, partly in elevation, taken substantially along the line Bfi of Fig. 5.

Fig. 7 is a longitudinal section, partly in elevation, taken substantially along the line 1-1 of Fig. 5.

Fig. 8 is a sectional view, partly in elevation, taken substantially along the line 88 of Fig. 7, looking in the direction of the arrows.

Fig. 9 is a section taken along t line Fig. '1.

Fig.1!) is an elevational view, somewhatv exaggerated, of a piston made in accordance with the method of my invention; and

Fig. 11 is a section taken substantially along the line Il -Il of Fig. 10.

Before explaining in detail the present invention it is to be understood that the invention is notlimited in its application to the details of:

construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways.

Also it is to be understood that the phraseolo li'u or terminology employed herein is for the purpose of' description and .not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior art.

Referring now particularly to the drawings, in,

plied. In the present instance, the machine is; provided with work holders which support thework at opposite ends and permit it to be rotated relatively to a rotatable longitudinally and laterally adjustable grinding wheel or element.

The machine shown is adapted for use in grinding cylindrical or round objects, such for example as pistons, to produce a piston having an external wall or periphery, the contour of which is out-of-round at the two opposite faces adjacent the piston pin, bosses. The mechanism embodying my invention is adapted to be detachably and interchangeably mounted upon the machine and comprises, as shown, separate units adapted to support the work at opposite ends, rotate the work, and impart to the opposite ends of the work an oscillatory motion, during rotation, which oscillation is independent at the opposite ends of the work. The mechanism of my invention is associated and timed to operate in conjunction with the driving or operating mechanism of the grinding machine.

,ReferringtoFig. 1, l5 designates, asa whole, "a mean of the base or supporting structure of a standard grinding machine, and I6 is a bed plate or table upon which the work actuating units l8 and I9 are adjustably mounted. At the left end of the machine an upright bracket or housing I1 is supported upon the base and provides a bearing for a main drive shaft 20. At 2| is shown a driven shaft by which one end struction a relatively large bearing 26 is mounted, I

through which the shaft 22 extends. I 3

At 2'! there is shown, as a whole, one of the work supporting and rotating members, the reference character 28 designating as a whole, the

other work support, the supports forming a part in the forked end of an arm 3|.

of the present invention. Cams, 29 and 30 are mounted at spaced points upon the. enlarged portion 22a of the driven shaft. The cam 29 cooperates with a roller 32 rotatably mounted The cam 30 cooperates with a roller 34 which is mounted in the forked end of an arm 33. These arms and rollers are best shown in Figs. 2 and 5. A spring tile is attached at one end to the arm 3| and 5 at its opposite end to the bed plate of the machine and serves to apply tension to the arm to maintain the roller 32 in contact with the cam 29. A similar tension spring 31 serves to hold the roller 34, carried by the arm 33, in contact with 30 the cam 30.

Referring particularly to Fig. 2, 3|b designates as a Whole, a post or rod extending above and below the axis of oscillation of the arm 3|. Tension springs 3|c are connected with the opposite ends of the post and are also attached to the face of the unit I8 to apply additional tension to the arm to resist its rocking or oscillating movement and any tendency of the roller to move away from the cam, as fully described hereinafter.

. Referring now particularly to Fig. 3, the inner end of the shaft 2| is provided with an enlargement 2|a and a tapered end portion 2|b, the purpose of the taper being to fit within an eccentric bushing to be described below. The Work support 21 is rotatably connected with the shaft 2| through the medium of a connecting link or shaft and a pair of universals 4| and 42 which are connected with the shaft end 2|b and a sleeve 43 which telescopes over the bushing, respectively. The inner i. e., exposed end of the sleeve is reduced to provide a substantially cylindrical portion 43a and has a forward extension 431) upon which is detachably mounted, by means of a pin 430, a shiftable block or member 45 which is adapted to fit within the space between the piston pin bosses of a piston. shown as a whole at P. The cylindrical portion 43a carries a frusto-conical member 44 upon which the lower end of the'skirt portion of the piston rests when the work is in position to be ground by the wheel G. W. Located within the sleeve 43 and mounted upon the end 2| 1) of the driven shaft,.is an eccentric bushing 46 having a flange 46a. A bearing, such as a ball or roller bearing assembly 47 surrounds the shaft 2| and is interposed'between the enlargement 2la and the flange 46a of the eccentric bushing. The opposite end of the bushing engages a-similar ball or roller bearing assembly 48 which is interposed between the eccentric bushing and the portion 43a. of the sleeve. The parts are preferably held together by a plate 49 and a plurality ofbolts 50. It will be seen that these bolts ,pass through the annular portion of the arm 3|, thus clamping furcated portion 33o.

said arm to the flange 46a of the eccentric bushing. Suitable packing is provided between the shaft and the several parts as shown in Fig. 3. A packing compressing device is also provided which comprises a substantially cylindrical portion 5| and a flange 52. The bolts 50 serve to maintain the device in place and permit it to be tightened when and if necessary.

It is to be noted that the universal connection between the driven shaft end 2H) and the work support 21 permits the axis of the work support to beoffset with respect to the axis of the shaft.

In practice, these axes are offset with respect to one another approximately one quarter inch, although the distance may be varied in accordance with the requirements of the machine and the particular work to be performed. Any suitable lubricating device may be used to lubricate the parts, there being shown, merely by Way of example, a gravity type lubricator 53.

I Referring now particularly to Figs. 7, 8, and 9 wherein the other work support 28 is shown in detail, the unit or housing i9 is provided with a bore |9a in which is located a sleeve which projects beyond the inner face of the member l9. The sleeve has a key-way or slot 55a formed therein and is held against rotation by a locking key or member 56 secured in place by cap screws 51. The work support comprises acylindrical portion 58 having an enlarged end portion 58a and an eccentric bore adapted to receive the tapered portion 550. of a stub shaft 55, the latter being located within the tapered bore of the fixed sleeve or support 55. The portion 65a is provided with oil grooves 65b. A work engaging and supporting center or pin 66 extends into a bore formed in the portion 58 and terminates just short of the fiat end of the tapered shaft portion 65a. The shaft 65 has an enlargement 62 which engages a ball or roller bearing assembly 50 located within the portion 580.. The parts are held together in position upon the shaft 65 by a closure plate I03 and a series of bolts 59. The portion 33a of the arm 33 is secured to the work support and is clamped in place against the member 580, by the bolts 59, so that rocking or oscillatory movement of the arm will impart va corresponding movement to the member 58 relative to the shaft 65. The end or tip of the center or pin 66 is adapted to engage in a recess formed in the head of the piston P to support that end of the piston.

It is desirable at times to adjust the position of the supporting center or pin 66 so as to bring the center line or axis of this pin to coincide with the center line or axis of the supporting cone 44, in order that the piston may be ground straight on the faces at right angles to the piston bosses PB, or to adjust the supporting center or pin 65 to bring its center line out of line with the center line of the cone 44, so as to produce tapered surfaces at right angles to the pin bosses PB as Well as a tapered surface adjacent the pin bosses.

Referring to Fig. 5, the arm 33 comprises a forward member or portion 33 and a rear mem ber 38a, these members having respectively upper extensions or lugs 33b and 330. The forward portion 33 has a bifurcated or forked rear extension 33d and a lower rear extension or bi- The latter portion provides a pivotal connection between the parts by means of bolt 33 The upper bifurcation or fork 33d engages the portion 330:, and is provided with a locking device having a handle for actu- 'ating' it, said'lockin'g device being shown as a 'wholeat33'y'.

To effect" relative adjustment of the portions 33 and 33a, the locking device 'is'released and the adjusting screw 35 is manipulated to separate or bring together the upward extensions 33b and 330. This causes both members 33 and 33a to revolve around the bolt 33 and the member 33a, in turn, is revolved around the center line of the member 65, thus swinging member 58, which holds the center or supporting pin 66 away'from the grinding wheel or toward it, dependent upon which way the screw 35 is manipulated.

Separation'of the upper extensions 33b and 330 swings the work away from the grinding wheel and manipulation of the screw 35 so as to move the upper extensions 33b and 330 toward each other swings the center 66 toward the grinding wheel. Each of these members is provided with a lug on-its top face, which lugs are interconnected by means of a tension spring 36, the purpose of which is to draw lug 330 against the site walls or portions C,. and the straight" grinding is done on the two opposed sides at right angles to the piston pin walls. As is well known, the head of a piston expands to a greater extent than the skirt thereof due to the excessive heat to which the'head is subjected. It is further known that the expansion takes placein the direction of the piston .pin bosses, s'o-that the piston, under heat, assumes a' substantially oval shape. Such expansion causes the piston to bind or freeze in the cylinder. It is known that by grinding the opposed surfaces adjacent the piston pin bosses, the reduced diameter-at these points compensates for the expansion of the piston. With respect to the effect of heatupon the skirt, it is known that the heat transmitted to the skirt from the head is dissipated to a greater degree at points removed from the head in the direction toward the lower end of the skirt. The top portion of the skirt adjacent the head expands to a greater degree than the lowerwportion thereof. Moreover, this expansion is greatest at the opposed faces or walls adjacent the piston pin bosses. For this reason, it is desirable to grind these particular faces of the piston out-of-round on a taper longitudinally of the piston, with the taper increasing toward the head end of the piston.

Operation of the machine As shown by Fig. 1, a piston P is positioned between the work supports 21 and 28 which engage it and maintain the piston in position adjacent the periphery of the grinding wheel G. W. Inasmuch as the grinding wheel per se forms no part of the present invention, except that it is used in connection with my improved mechanism'for grinding'articles out-of-round, it is not deemed necessary to show or discuss it more in detail. It will suffice to say that the grinding wheel is driven by suitable mechanism connected withthe drive mechanism for the other parts of themachine, 'and that it is adjustable longitudinally relatively to'the work, i. e. lengthwise of the machine, and also laterally, i. e. crosswise of the machine from front to back and vice versa, so that it may be moved, first into contact with the work, and then longitudinally along the face or periphery of the work to perform the grinding operation.

It is: well known that it is highly desirable, as

set forth above, to provide a piston having an outer surface or peripheral wall which is out-ofround, and that it is further desirable that the out-of-round' portions of the piston be located on the opposite faces adjacent and surrounding the piston pin'bosses. Accordingly, I have provided the foregoing improved mechanism for supporting and rotating the work and for further imparting to the work an oscillatory motion independently at opposite ends of the work to permit the grinding wheel to grind two opposed faces of the piston wall adjacent the'piston pin bosses out-of-round and the remaining two walls round or cylindrical, during each revolution of the piston; and to further regulate and control the oscillatory'or shifting movement of the opposite ends vof the piston so as to produce, on the two opposed ground faces which are out-of-round, a taper Lwhich extends longitudinally of the piston. As

shown, this taper occurson opposite faces adjacent the piston pin bosses and extends from the lower end of the skirttoward the head of the piston, increasing toward the head .end. It is, however, entirely within the scope of my invention to extend the aforesaid grinding operation to include the head portion also of the piston, if and when desirable. It is also within the purview of my invention to impart to a piston or any similar round or cylindricalobject, a grinding operation which produces a pair of out-of-round portions or faces on anytwo surfaces which are opposed to one another.- The out-of-round portions of the piston merge with the cylindrically ground portions thereof in such a manner that the junction of the dissimilarly ground portions is not discernible.

In practice, a piston is inserted between the members 27 and 28, with the skirt portion thereof engaging the frusto-conical member 44 and the head portion engaging the end or tip of the center or pin 65. After the piston is in position, with the block or member 45 fitting snugly within the space between the piston pin bosses, power is applied to the shaft 2|] through the medium of the power belt I22 and pulley l2l to rotate the work support, 2'1 and the piston relative to the work support 28 at the headend of the piston. Referring now particularly to Figs. 3 and 7, which show in detail the work supporting members, the frusto-conical member 44 and the block 45 are rotated on an-axis which is offset with respect to the axis of rotationof the driven shaft 2|, this offset relation being permitted by reason of the universal connection 40, 4|, 42 between the shaft and the work support. When the shafts 20 and 2| are rotated, the shaft 22 is likewise rotated, there being suitable reduction provided by means of the chain and sprockets 25, one of which members is adjustable on the shaft to properly time the cams and to impart to the sev- "eral shafts the proper speed of rotation. As the shaft 22 rotates, the cams '29 and 3|] are likewise rotated and inasmuch as these cams engage, respectively, the rollers 32 and 34 carried by the arms 3| and 33, it will be seen that these arms are given a rocking motion. Thearm 3|, being connected with the eccentric bushing 46, causes an oscillation of said bushing about which the sleeve 43 is rotating, thus causing a shifting or off-center oscillation of the work support 21 and likewise the skirt end of the piston. The tension springs 3m and 3lc (-Fig. '2) serve to maintain the roller 32 in constant engagement with the cam 29 to produce a constant and accurate oscillation of the eccentric bushing and work sup port. The: arm 33a is directly connected with the other work support 28 and as the cam 30 is rotated by the shaft it engages the roller 34 and imparts to the arm a similar rocking movement which causes an oscillation of the work support 28. It is to be noted that the axis of the pin 66 is offset with respect to the axis of rotation of the shaft 65, thus causing an off-center or cranklike oscillation or shifting of the work support 28 and the head end of the piston. During the foregoing action the grinding wheel is being rotated constantly to grind the entire periphery or outer faces of the piston to produce a pair of out-ofround faces or portions adjacent and surrounding the piston pin bosses, and another pair of opposed cylindrical faces or portions at right angles to the bosses. The cams 29 and 30, as shown,

are dissimilar, since, where it is desirable to provide the piston with a pair of out-of-round sections or portions which are tapered, the degree or amount of oscillating motion imparted to the work support 2'! is materially less than that imparted to the work support 28. If, however, opposed out-of-round sections or faces which are r not tapered, are desired, the two cams 29 and 30 would be substantially identical.

While I have described above and illustrated in the drawings, merely by Way of example, a shaft or spindle which rotates on a fixed axis and a work holder which ispositioned off-center with respect to the spindle and is driven from it by a universal connection, together with an adjmst'able eccentric for varying the oscillatory movement of the work holder, it is contemplated by my invention that the work spindle itself may be mounted to rotate within an eccentric sleeve, which eccentric sleeve is adjustable in substantially the same manner by means of a cam, as above described. In such instance, the work holder will be oscillated by virtue of a fixed offcenter connection with the shaft or work spindle, rather than through a variable off-center connection by virtue of the universal joints or connection herein shown. The variation of the oscillatory movement would be obtained by the cam oscillating the eccentric within which the work spindle rotates instead of the eccentric on which the work holder rotates.

I claim:

1. In a machine for grinding a cylindrical piece of work, such as a piston, the combination of a rotary grinding member for grinding the periphery of thework, a pair of work holders for supporting opposite ends of the work in position to be operated upon by said grinding member, means for rotating the work through one of said work holders, means for relatively moving the work and grinding member in a longitudinal direction, cam means for imparting an oscillatory movement to both of said work holders thereby to grind two opposite faces of the Work out-of-round, and eccentric means for varying the oscillatory movement of one work holder relatively to the other work holder.

2. In amachine for grinding a cylindrical piece of work,such as a piston, the combination of a rotary grinding member for grinding the entire circumference of the work, a pair of work holders for supporting opposite ends of the work in position to be operated upon by said grinding member, means for rotating the work through one of said work holders, means for relatively moving the work and grinding member in a longitudinal direction, cam means for imparting an oscillatory movement to both of said work holders thereby to grind two opposite faces of the work out-ofround, and eccentric means for varying the oscillatory movement of each work holder.

3. In a machine for grinding a cylindrical piece of work, such as a piston, the combination of a rotary grinding member for grinding the entire out-of-round, and adjustable eccentric means for varying the oscillatory movement of each work holder and one relatively to the other.

4. In a machine for grinding a cylindrical piece of work, such as a piston, the combination of a rotary grinding wheel for grinding the periphery of the Work, a pair of work holders for supporting opposite ends of the work in position to be operated upon by said grinding wheel, means for rotating/the work, cam means for oscillating each work holder to shift the work relative to the grinding wheel twice during each revolution of the work, thereby to grind two opposed faces of the work out-of-round, and means for varying the oscillatory movement of one work holder relatively to the other. I

5. In a-machine for grinding a cylindrical piece of work, such as a piston, the combination of a rotary grinding member for continuously grinding the periphery of the work, rotary work holders for independently supporting opposite ends of the work, and mechanism comprising a driven cam and an oscillatable arm carrying a roller with which said cam contacts for shifting the work twice during each rotation thereof relatively to the grinding member to grind predetermined opposed faces of the work cylindrically and other faces of the work out-of-round on a taper extending longitudinally of the work, said taper occurring only on the two opposed. out-of-round faces of the work.

6. In a machine for grinding a piston, the combination of a rotary grinding member for continuously grinding the periphery of the piston, rotary work holders for independently supporting opposite ends of the piston, and mechanism including a driven cam and a rocking arm provided at its free end with a cam engaging roller for independently shifting opposite ends of the piston twice during each rotation thereof relatively to the grinding member to grind predetermined faces of the circumference of the piston cylindrically and other faces of the piston out-of-round on a taper extending longitudinally of the piston only at the out-of-round faces thereof.

7. In a machine for grinding a cylindrical piece of work, such as a piston, the combination of a rotary grinding wheel for grinding the entire circumference of the work, a pair of work holders for supporting opposite ends of the work in position to be operated upon by said grinding Wheel, each revolution of the work at equally timed intermeans for rotating said work holders, and means vals, thereby to grind two opposed faces of the including a driven cam and an oscillatable arm work out-of-round and the other faces of the provided with a roller with which said cam con- Work cylindrical.-

5 tacts for oscillating each work holder to shift the NORMAN B. CHACE, JR. 5

work relative to the grinding wheel twice during 

